svn commit: r195960 - in head/sys/dev/usb: . controller input

Robert N. M. Watson rwatson at
Sun Aug 2 19:58:17 UTC 2009

On 2 Aug 2009, at 20:29, Alfred Perlstein wrote:

> * Robert Watson <rwatson at> [090801 15:15] wrote:
>> On Sat, 1 Aug 2009, Hans Petter Selasky wrote:
>>>>> This has slowed down core dumps very significantly.  What used  
>>>>> to take
>>>>> 10-15s on my system now takes around 3 minutes.  A simple test  
>>>>> is to
>>>>> break into ddb and "call doadump" with or without this rev.  I  
>>>>> have a
>>>>> serial console on this machine and so I can use ddb whether the  
>>>>> attached
>>>>> USB keyboard works or not.
>>> It's because there is a DELAY(1000) in the UKBD's polling routine  
>>> so that
>>> key- repeating will work, no magic.
>> Given a choice between dumping 10x faster and having automatic key  
>> repeat
>> in DDB, I'd lean towards the former.  :-)
> Robert, and *,
> Hans should be back in a day or so to address this.  If critical I can
> probably back out the offending code, but I think it makes sense to
> wait a few days more for a more comprehensive fix.

That's my feeling too -- however, I think it would be useful to  
generate a small concept test patch that disables the key repeat  
behavior and see if it restores some/all performance. Scott's argument  
suggests only some, but perhaps we'd get quite a bit, which is what  
we're looking for. We wouldn't commit the patch but it would let us  
know we're on the right track.


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